DESC: "The 4WTA-B is a 4-wire, photoelectric i3 smoke detector device with thermal detector and built-in sounder. Specifications: Detection: Photoelectric Wiring: 4-wire Heat Sensor: 135F (57.2C) fixed Sounder: 85 dBA Operating Voltage: 12/24 V non-polarized nominal, 10 min. to 35 max. Maximum Ripple Voltage: 30% of nominal (peak to peak) Alarm Current: 35mA max. Standby Current: 50A maximum average Alarm Contact Ratings: 0.5A @ 30V AC/DC Temperature Range: 32 to 100F (0 to 37.8C) Humidity Range: 0% to 95% RH, noncondensing Freeze Trouble: 41F (5C) Sensitivity: 2.5%/ft. nominal Wiring Gauge: 14-22 AWG Dimensions: 2.0"" (51mm) H x 5.3"" (127mm) Dia. Weight: 7.1 oz. (200 g)"